1. Technical Field
The present invention generally relates to terminals for interconnecting electrical components. More particularly, the present invention relates to audio signal terminals for selectively establishing parallel or series connections between loads connected thereto.
2. Related Art
While significant improvements have been made in the development of high power loudspeakers, alternative solutions that utilize existing loudspeakers have been considered because of increased costs associated therewith. These alternative solutions have involved connecting the loudspeakers in series or in parallel for enhanced performance. The loudspeakers are connected to an audio signal source, which may be a stereo receiver, an amplifier, etc. As is generally understood, a series connection of multiple loudspeakers increases the load impedance, resulting in a more efficient operation of the audio signal source. However, with the increase in load impedance, there is a decrease in the voltage applied to each loudspeaker and a consequential decrease in the audio output of the same. On the other hand, parallel connections decrease the load impedance, and while each loudspeaker is applied a constant voltage level, current draw on the audio signal source increases.
In addition to individual loudspeakers having single voice coils, recent advances in loudspeakers, particularly in woofers and subwoofers, have introduced the use of multiple voice coils in a single loudspeaker. Dual voice coil subwoofers have two separate electrically isolated windings mounted to a common bobbin. Such loudspeakers are frequently used in car audio applications for increased flexibility in wiring. While power handling levels, frequency response, and other parameters remain the same whether connected in series or in parallel, the impedance “seen” by the audio signal source changes.
A number of devices to connect multiple loudspeakers or multiple voice coil elements of a single loudspeaker in parallel or in series have been contemplated. One is U.S. Pat. No. 6,656,000 to Abdo, which essentially teaches a pair of metallic blocks, a first block being electrically connected to a positive line from the audio signal source and a second block being electrically connected to a negative line from the audio signal source. The first block includes a pair of output terminals to be connected to the respective one of positive wires of the loads (voice coil element). The second block likewise includes a pair of output terminals to be connected to the respective one of negative wires of the loads. Such first embodiment is operative to connect the loads in parallel. A second embodiment includes essentially the same components, but includes only one output terminal for each block. Thus, the positive wire of one of the loads is connected to the first block, the negative wire of one of the loads is connected to the positive wire of the other load, and the negative wire of the other load is connected to the second block, connecting the loads in series. Another is the Applicant's co-pending U.S. patent application Ser. No. 11/453,647, entitled “Terminal Assembly for Selectively Coupling Loads in Parallel and In Series,” which is wholly incorporated by reference herein.
As will be appreciated by one of ordinary skill in the art, the Abdo device essentially provides an accessible central junction for connecting the audio signal source and the wires of the loads. However, such prior devices are deficient in that it is still necessary to handle the actual wires of the loads to alter the configuration between series wiring and parallel wiring. Additionally, it is necessary to substitute different terminal blocks to switch between series wiring and parallel wiring. One major difficulty experienced by consumers in altering the configuration of loudspeakers is the clutter associated with handling the wires, and being unable able to ascertain whether the proper connections have been made. Therefore, there is a need in the art for an improved terminal assembly which can more readily switch the wiring configuration of electrical loads from parallel to series, and vice versa.